SLVS885I
October 2008 – December 2017
TPS23754
,
TPS23754-1
,
TPS23756
PRODUCTION DATA.
1
Features
2
Applications
3
Description
Device Images
High-Efficiency Converter Using TPS23754
4
Revision History
5
Pin Configuration and Functions
Pin Functions
6
Specifications
6.1
Absolute Maximum Ratings
6.2
ESD Ratings
6.3
Recommended Operating Conditions
6.4
Thermal Information
6.5
Electrical Characteristics
6.6
Electrical Characteristics: PoE and Control
6.7
Switching Characteristics
6.8
Typical Characteristics
7
Detailed Description
7.1
Overview
7.2
Functional Block Diagram
7.3
Feature Description
7.3.1
APD
7.3.2
BLNK
7.3.3
CLS
7.3.4
Current Sense (CS)
7.3.5
Control (CTL)
7.3.6
Detection and Enable (DEN)
7.3.7
DT
7.3.8
Frequency and Synchronization (FRS)
7.3.9
GATE
7.3.10
GAT2
7.3.11
PPD
7.3.12
RTN, ARTN, COM
7.3.13
T2P
7.3.14
VB
7.3.15
VC
7.3.16
VDD
7.3.17
VDD1
7.3.18
VSS
7.3.19
PowerPAD
7.4
Device Functional Modes
7.4.1
PoE Overview
7.4.1.1
Threshold Voltages
7.4.1.2
PoE Start-Up Sequence
7.4.1.3
Detection
7.4.1.4
Hardware Classification
7.4.1.5
Inrush and Start-Up
7.4.1.6
Maintain Power Signature
7.4.1.7
Start-Up and Converter Operation
7.4.1.8
PD Hotswap Operation
7.4.1.9
Converter Controller Features
7.4.1.10
Bootstrap Topology
7.4.1.11
Current Slope Compensation and Current Limit
7.4.1.12
Blanking – RBLNK
7.4.1.13
Dead Time
7.4.1.14
FRS and Synchronization
7.4.1.15
T2P, Start-Up, and Power Management
7.4.1.16
Thermal Shutdown
7.4.1.17
Adapter ORing
7.4.1.18
PPD ORing Features
7.4.1.19
Using DEN to Disable PoE
7.4.1.20
ORing Challenges
8
Application and Implementation
8.1
Application Information
8.2
Typical Application
8.2.1
Design Requirements
8.2.2
Detailed Design Procedure
8.2.2.1
Input Bridges and Schottky Diodes
8.2.2.2
Protection, D1
8.2.2.3
Capacitor, C1
8.2.2.4
Detection Resistor, RDEN
8.2.2.5
Classification Resistor, RCLS
8.2.2.6
Dead Time Resistor, RDT
8.2.2.7
Switching Transformer Considerations and RVC
8.2.2.8
Special Switching MOSFET Considerations
8.2.2.9
Thermal Considerations and OTSD
8.2.2.10
APD Pin Divider Network, RAPD1, RAPD2
8.2.2.11
PPD Pin Divider Network, RPPD1, RPPD2
8.2.2.12
Setting Frequency (RFRS) and Synchronization
8.2.2.13
Current Slope Compensation
8.2.2.14
Blanking Period, RBLNK
8.2.2.15
Estimating Bias Supply Requirements and CVC
8.2.2.16
T2P Pin Interface
8.2.2.17
Advanced ORing Techniques
8.2.2.18
Soft Start
8.2.2.19
Frequency Dithering for Conducted Emissions Control
8.2.3
Application Curves
9
Power Supply Recommendations
10
Layout
10.1
Layout Guidelines
10.2
Layout Example
10.3
ESD
11
Device and Documentation Support
11.1
Documentation Support
11.1.1
Related Documentation
11.2
Community Resources
11.3
Trademarks
11.4
Electrostatic Discharge Caution
11.5
Glossary
12
Mechanical, Packaging, and Orderable Information
6.8
Typical Characteristics
Figure 2.
Detection Bias Current vs Voltage
Figure 4.
'754 Converter Start Time vs Temperature
Figure 6.
'754 Converter Start-Up Current vs V
VDD1
Figure 8.
Controller Bias Current vs Temperature
Figure 10.
'756 Controller Bias Current vs Voltage
Figure 12.
Switching Frequency vs Program Conductance
Figure 14.
Current Slope Compensation Voltage vs Temperature
Figure 16.
Blanking Period vs Temperature
Figure 18.
Dead Time vs Dead Time Resistance (R
DT
)
Figure 3.
PoE Current Limit vs Temperature
Figure 5.
'756 Converter Start Time vs Temperature
Figure 7.
'756 Converter Start-Up Current vs V
VDD1
Figure 9.
'754 Controller Bias Current vs Voltage
Figure 11.
Switching Frequency vs Temperature
Figure 13.
Maximum Duty Cycle vs Temperature
Figure 15.
Current Slope Compensation Current vs Temperature
Figure 17.
Blanking Period vs Blanking Resistance (R
BLNK
)
Figure 19.
T2P Delay Time vs Temperature